This proposal seeks to understand in detail the role of alpha-lactalbumin in lactose biosynthesis ("lactose synthetase"). Alpha-lactalbumin, a common milk protein both plays an important regulatory role and is itself subject to a fine regulation at the levels of organ specificity, cellular structure and hormonal control of both its biosynthesis and secretion. In more detail this work is directed at examining structure, conformation and changes therein associated with galactosyl transferase function at the molecular level. This research utilizes the extremely powerful techniques of magnetic resonance to investigate the interactions of both substrates and the two proteins (galactosyl transferase and alpha-lactalbumin) involved in the biosynthesis of lactose.